The manner in which extracellular matrix components produced by the corneal fibroblast are assembled into the precisely organized corneal stroma necessary for optical transparency will be investigated. The role of the corneal fibroblast cell surface in the control of collagen fibrillogenesis, bundle and lamellae formation will be studied by transmission, and scanning electron microscopy and by high voltage electron microscopy. The surface topography of these cells and their relationship to the extracellular matrix will be established after three dimensional reconstruction from 0.5 Mum serial sections examined by high voltage electron microscopy. Immunoelectron microscopy with antibodies to the carboxy and amino terminal propeptides of type I collagen will be used to determine the role of these peptides and their processing in the control of fibril formation and fibril diameter. Monoclonal antibodies to type V collagen will be used to study the distribution and interaction of this collagen with respect to corneal type I collagen. These morphological studies will be coupled with in vitro studies on type I and V interactions in fibril formation and an analysis of fibril structure. This will extend our knowledge of the role of type V collagen in the development of connective tissue architecture. The influence of proteoglycans on fibril formation, control of fibril diameter and interfibrillar spacing will be studied morphologically using histochemical methods coupled with enzymatic digestions in normal corneal stroma and after inhibition of glycosaminoglycan synthesis with inhibitors. These studies on the regulation of corneal fibril formation contribute to our understanding of the mechanisms by which the precise collagen architecture associated with corneal transparency is controlled during development, growth, injury and repair.